An axial Hox code controls tissue segmentation and body patterning in Nematostella vectensis

Science ◽  
2018 ◽  
Vol 361 (6409) ◽  
pp. 1377-1380 ◽  
Author(s):  
Shuonan He ◽  
Florencia del Viso ◽  
Cheng-Yi Chen ◽  
Aissam Ikmi ◽  
Amanda E. Kroesen ◽  
...  
Keyword(s):  
Hox Genes ◽  
Bilateral Symmetry ◽  
Nematostella Vectensis ◽  
Tissue Segmentation ◽  
Hairpin Rna ◽  
Orthogonal Axis ◽  
Body Patterning ◽  
Hox Code ◽  
Short Hairpin ◽  
Anterior Posterior

Hox genes encode conserved developmental transcription factors that govern anterior-posterior (A-P) pattering in diverse bilaterian animals, which display bilateral symmetry. Although Hox genes are also present within Cnidaria, these simple animals lack a definitive A-P axis, leaving it unclear how and when a functionally integrated Hox code arose during evolution. We used short hairpin RNA (shRNA)–mediated knockdown and CRISPR-Cas9 mutagenesis to demonstrate that a Hox-Gbx network controls radial segmentation of the larval endoderm during development of the sea anemone Nematostella vectensis. Loss of Hox-Gbx activity also elicits marked defects in tentacle patterning along the directive (orthogonal) axis of primary polyps. On the basis of our results, we propose that an axial Hox code may have controlled body patterning and tissue segmentation before the evolution of the bilaterian A-P axis.

scholarly journals Hox genes regulate asexual reproductive behavior and tissue segmentation in adult animals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christopher P. Arnold ◽  
Analí Migueles Lozano ◽  
Frederick G. Mann ◽  
Stephanie H. Nowotarski ◽  
Julianna O. Haug ◽  
...  
Keyword(s):  
Asexual Reproduction ◽  
Hox Genes ◽  
Adult Stage ◽  
Tissue Segmentation ◽  
Hox Gene ◽  
Downstream Effector ◽  
Effector Genes ◽  
And Behavior ◽  
Insight Into ◽  
Anterior Posterior

AbstractHox genes are highly conserved transcription factors renowned for their roles in the segmental patterning of the embryonic anterior-posterior (A/P) axis. We report functions for Hox genes in A/P tissue segmentation and transverse fission behavior underlying asexual reproduction in adult planarian flatworms, Schmidtea mediterranea. Silencing of each of the Hox family members identifies 5 Hox genes required for asexual reproduction. Among these, silencing of hox3 genes results in supernumerary fission segments, while silencing of post2b eliminates segmentation altogether. The opposing roles of hox3 and post2b in segmentation are paralleled in their respective regulation of fission behavior. Silencing of hox3 increases the frequency of fission behavior initiation while silencing of post2b eliminates fission behavior entirely. Furthermore, we identify a network of downstream effector genes mediating Hox gene functions, providing insight into their respective mechanisms of action. In particular, we resolve roles for post2b and effector genes in the functions of the marginal adhesive organ in fission behavior regulation. Collectively, our study establishes adult stage roles for Hox genes in the regulation of tissue segmentation and behavior associated with asexual reproduction.

scholarly journals Hox genes pattern the primary body axis of an anthozoan cnidarian prior to gastrulation

2017 ◽  
Author(s):  
Timothy Q. DuBuc ◽  
Thomas B. Stephenson ◽  
Amber Q. Rock ◽  
Mark Q. Martindale
Keyword(s):  
Transcription Factors ◽  
Wnt Signaling ◽  
Hox Genes ◽  
Opportunity To Learn ◽  
Sister Group ◽  
Nematostella Vectensis ◽  
Sea Anemones ◽  
Positional Identity ◽  
Primary Body ◽  
Anterior Posterior

Hox gene transcription factors are important regulators of positional identity along the anterior-posterior axis in bilaterian animals. Cnidarians (e.g. sea anemones, corals and hydroids) are the sister group to the Bilateria and possess genes related to both anterior and central/posterior class Hox genes. In the absence of a conserved set of Hox genes among other early branching animal clades, cnidarians provide the best opportunity to learn about the emergence of this gene family. We report a previously unrecognized domain of Hox expression in the starlet sea anemone, Nematostella vectensis, beginning at early blastula stages. Functional perturbation reveals that two Hox genes not only regulate their respective expression domains, but interact with one another to pattern the entire oral-aboral axis mediated by Wnt signaling. This suggests an ancient link between Hox/Wnt patterning of the oral-aboral axis and suggest that these domains are likely established during blastula formation in anthozoan cnidarians.

scholarly journals Hox genes regulate asexual reproductive behavior and tissue segmentation in adult animals

2021 ◽  
Author(s):  
Christopher P. Arnold ◽  
Analí Migueles Lozano ◽  
Frederick G. Mann ◽  
Jeffrey J. Lange ◽  
Christopher Seidel ◽  
...  
Keyword(s):  
Asexual Reproduction ◽  
Hox Genes ◽  
Mechanisms Of Action ◽  
Adult Tissue ◽  
Tissue Segmentation ◽  
Downstream Effector ◽  
Effector Genes ◽  
And Function ◽  
Insight Into ◽  
Anterior Posterior

SummaryHox genes are highly conserved transcription factors renowned for their roles in the segmental patterning of the embryonic anterior-posterior (A/P) axis1. Emerging evidence for Hox gene expression and function in postnatally derived structures has fueled interest in their additional roles beyond embryogenesis2,3. We report novel functions for Hox genes in A/P adult tissue segmentation and transverse fission behavior underlying asexual reproduction in the planarian flatworm, Schmidtea mediterranea. Silencing of each of the planarian Hox family members identified 5 Hox genes required for asexual reproduction. Among these, silencing of hox3 genes resulted in supernumerary segments, while silencing of post2b eliminated segmentation altogether. The opposing roles of hox3 and post2b in segmentation are paralleled in their respective regulation of fission behavior. Silencing of hox3 increased the frequency of fission behavior initiation, while silencing of post2b eliminated fission behavior entirely. Furthermore, we identified a network of downstream effector genes mediating Hox gene regulation of asexual reproduction, thereby providing insight into their respective mechanisms of action. Our study establishes postembryonic roles for Hox genes in regulating the emergence of tissue segmentation and specific behaviors associated with asexual reproduction in adult animals.

scholarly journals Large-Scale, High-Throughput Validation of Short Hairpin RNA Sequences for RNA Interference

2006 ◽  
Vol 11 (3) ◽  
pp. 236-246 ◽  
Author(s):  
Laurence H. Lamarcq ◽  
Bradley J. Scherer ◽  
Michael L. Phelan ◽  
Nikolai N. Kalnine ◽  
Yen H. Nguyen ◽  
...  
Keyword(s):  
High Throughput ◽  
Large Scale ◽  
Strong Support ◽  
Gc Content ◽  
Rapid Identification ◽  
Hairpin Rna ◽  
Rna Sequences ◽  
Short Hairpin ◽  
Short Hairpin Rnas ◽  
Interfering Rna

A method for high-throughput cloning and analysis of short hairpin RNAs (shRNAs) is described. Using this approach, 464 shRNAs against 116 different genes were screened for knockdown efficacy, enabling rapid identification of effective shRNAs against 74 genes. Statistical analysis of the effects of various criteria on the activity of the shRNAs confirmed that some of the rules thought to govern small interfering RNA (siRNA) activity also apply to shRNAs. These include moderate GC content, absence of internal hairpins, and asymmetric thermal stability. However, the authors did not find strong support for positionspecific rules. In addition, analysis of the data suggests that not all genes are equally susceptible to RNAinterference (RNAi).

scholarly journals Hox genes are essential for the development of eyespots in Bicyclus anynana butterflies

Genetics ◽  
2020 ◽  
Vol 217 (1) ◽  
Author(s):  
Yuji Matsuoka ◽  
Antónia Monteiro
Keyword(s):  
Hox Genes ◽  
Bicyclus Anynana ◽  
Hox Gene ◽  
Novel Traits ◽  
Anterior Posterior ◽  
Anterior Posterior Axis

Abstract The eyespot patterns found on the wings of nymphalid butterflies are novel traits that originated first in hindwings and subsequently in forewings, suggesting that eyespot development might be dependent on Hox genes. Hindwings differ from forewings in the expression of Ultrabithorax (Ubx), but the function of this Hox gene in eyespot development as well as that of another Hox gene Antennapedia (Antp), expressed specifically in eyespots centers on both wings, are still unclear. We used CRISPR-Cas9 to target both genes in Bicyclus anynana butterflies. We show that Antp is essential for eyespot development on the forewings and for the differentiation of white centers and larger eyespots on hindwings, whereas Ubx is essential not only for the development of at least some hindwing eyespots but also for repressing the size of other eyespots. Additionally, Antp is essential for the development of silver scales in male wings. In summary, Antp and Ubx, in addition to their conserved roles in modifying serially homologous segments along the anterior–posterior axis of insects, have acquired a novel role in promoting the development of a new set of serial homologs, the eyespot patterns, in both forewings (Antp) and hindwings (Antp and Ubx) of B. anynana butterflies. We propose that the peculiar pattern of eyespot origins on hindwings first, followed by forewings, could be due to an initial co-option of Ubx into eyespot development followed by a later, partially redundant, co-option of Antp into the same network.

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